Yes indeed. I love them when they have huge castles too. You kow what would be cool? A map with all abandoned castles that you have to capture and then fight. Oh another question which I think might have been asked, (if so sorry for double posting) can you take the remains of an enemy castle and build it up into another castle for your army?

I've always felt that buildings should leave behind ruins, and those ruins should in turn impart a discount if you build over them (re-using the destroyed structure, so to speak). Being able to capture walls should go without saying.

I don't think stone foundations are exactly worth money. I think being able to assume control of a base would be nice, but being able to liquidate it into resources could only feed what's commonly referred to as the "steamroller" effect, where the momentum from one victory inevitably leads to the next, resulting in imminent defeat for one player.